In E. coli, replication begins at which chromosome site?

oriC

What is the DNA replication fork?

It is the site where the DNA helix opens to two single DNA strands.

Okazaki fragments form on the lagging strand during DNA replication.

True

DNA replication in eukaryotes

initiates at multiple origins

DNA replication proceeds

semiconservatively

DNA replication occurs by adding

dNTPs to the 3′ end of the daughter strand

What are two distinguishing features of RNA?

RNA has a ribose sugar and uracil nitrogenous base.

What is the role of a promoter region of a gene?

Recruit transcription factors that form the initiation complex.

Which region(s) of a gene are not found within the mRNA transcript?

promoter and termination region

you want to design a drug that prevents transcription of eukaryotic mRNAs but does not affect transcription of other RNAs. What enzyme would you target?

RNA polymerase II

Which of the following is part of a DNA molecule?

Promoter

Which enzyme is required to initiate 5′ capping of eukaryotic mRNA transcripts by removing the terminal phosphate group?

guanylyl transferase

Which of the following bacterial RNA polymerase subunits is found in the holoenzyme, but not the core enzyme?

σ (sigma)

What is the general name for the components of the spliceosome, which removes introns from mRNAs?

small nuclear ribonucleoproteins

snRNA

What are catalytically active RNAs that can activate processes such as self-splicing?

ribozymes

What is the purpose of alternative splicing in eukaryotic cells?

Produce multiple polypeptide sequences from a single primary transcript.

Frederick Griffith studied how Pneumococcus causes fatal pneumonia in mice, focusing on the role of the capsule in the virulence of the bacteria. He found that heat-killed S bacteria somehow donated a molecule that was incorporated into living RII bacteria, which were converted from R to S capsules. He concluded that the basis of heredity was what?

a transforming factor

The antibiotic rifamycin is known to inhibit DNA polymerases in bacteria. What effect would this drug have on the structure of DNA?

It would be unable to form phosphodiester bonds between the 3′ hydroxyl group of one nucleotide and the 5′ phosphate group of an adjacent nucleotide.

How does base stacking contribute to the structure of DNA?

Nucleotide base pairs are spaced 3.4 Å apart, creating a twist to the double helix and two grooves within the backbone.

If Meselson and Stahl had used CsCl gradient analysis and identified DNA molecules with two distinct densities after generation 1, which model of DNA replication would have been supported by these data?

conservative

After how many replication generations were Meselson and Stahl able to distinguish semiconservative replication and dispersive replication.

2

Using pulse-chase labeling, Huberman and Riggs provided the first experimental evidence of bidirectional replication. What results would have supported the hypothesis that plasmid replication was actually unidirectional?

Alternating light and dark tracks in one direction from the replication origin

Which of the following is true regarding the Hershey Chase experiment?

The tagged phosphorus was present in the infected E.coli proving DNA is genetic information.

If a DNA sequence is made up of 30% Thymine, what percent of the DNA should be Cytosine?

20

If a DNA Sequence is 40% Guanine, what percent of the DNA sequence is Uracil?

0 (DNA does not have uracil)

Base pairs are covalently bonded together, adding structure to the DNA helix

false

What is a major difference between prokaryotic and eukaryotic DNA replication?

DNA replication in prokaryotes is bidirectional from one origin of replication, whereas eukaryotic replication is bidirectional from multiple origins of replication on each chromosome.

In E. coli, what is the function of the DnaB enzyme?

DnaB is a helicase protein that uses ATP energy to hydrolyze hydrogen bonds, which separates the DNA strands and unwinds the double helix.

DNA polymerase III initiates strand elongation by adding a new nucleotide to the 3′ end of a short primer sequence. Where does this short primer come from?

RNA polymerase

During DNA replication, one daughter strand has a 5′-to-3′ direction of elongation that runs opposite to the direction of movement of the replication fork. These daughter strands are elongated discontinuously, in short segments called Okazaki fragments. Which enzyme is involved in annealing these fragments together, once the RNA primers have been removed and replaced with DNA, to form a continuous, newly replicated strand?

DNA ligase

For the DNA strands of a circular chromosome, unwinding creates torsional stress that accumulates as the unwound region gets larger and as DNA replication progresses. The accumulating stress could break the molecule at random locations, potentially leading to a breakdown of DNA replication. How does the cell prevent this stress?

Through the action of topoisomerases, which catalyze a controlled cleavage and rejoining of DNA, thus enabling over-twisted strands to unwind

DNA polymerase I has a 5′-to-3′ polymerase activity, as well as both 5′-to-3′ and 3′-to-5′ exonuclease activities. Suppose a cell has acquired a mutation that eliminates only the 5′-to-3′ exonuclease activity of DNA polymerase I. What would be the effect on DNA replication?

RNA primers required for initiation of replication cannot be removed by DNA polymerase I.

Which of the following is the main function of DNA polymerase III

Main replication enzyme

Which of the following is NOT true regarding the formation of telomeres?

They are formed from a DNA template added by telomerase

Prokaryotic DNA does not replicate semiconservatively

false

DNA Polymerase requires a primer

true

If you were to design an antibiotic, which of these molecular features of transcription/translation would you NOT want to target? (Hint: you would want to target bacteria)

transcription factors

Which type of RNA is translated in a cell

mRNA

What are the only types of functional RNA observed in prokaryotes?

tRNA and rRNA

Which type of RNA regulates protein production through RNA interference

miRNA

How does RNA polymerase use DNA to synthesize an mRNA strand during transcription?

The polymerase uses one strand of DNA as the template strand to assemble a complementary, antiparallel strand of ribonucleotides.

Which DNA segment controls the access of RNA polymerase to the gene?

promoter

In bacteria, what structure triggers intrinsic termination of transcription?

Inverted repeats and a string of adenines

In eukaryotes, which enzyme is responsible for transcribing messenger RNAs that encode polypeptides, as well as for most small nuclear RNA genes?

RNA Polymerase II

The TATA box is an important conserved sequence within a gene. What is its primary function?

The TATA box acts as a highly conserved sequence within the eukaryotic promoter, which is located just upstream of the transcriptional start site.

Cancer cells often make their own transcription factors (TFs), which accounts for their increased growth rate. What effect would you expect to see when TF levels are increased in a cell?

Transcription would increase.

Which DNA sequence binds activator proteins and associated coactivator proteins to form a protein "bridge" that bends the DNA and links the complete initiation complex at the promoter to the activator-coactivator complex, ultimately causing an increase in transcription?

enhancer

Pre-mRNA must undergo 5′ capping to increase stability of the transcript. What two steps occur during 5′ capping?

Addition of guanine to the transcript and subsequent methylation

Introns are removed from mRNA by the spliceosome, a complex made up of protein and what type of RNA?

snRNAs

In posttranscriptional processing in Eukaryotes, the poly-A tail is encoded in the actual gene code

false

In prokaryotic intrinsic termination, the poly A tail is encoded by the gene code

true

Which of the following statements is false?

DNA always determines the final mature mRNA nucleotide sequence.

know how to code template strands?

kkk

What is this consensus sequence called?

Pribnow Box

Is this DNA prokaryotic or eukaryotic?

Prokaryotic

Where is it located relative to the start of transcription?

10 Nucleotides upstream

Which strand is the template strand?

5'-3'

Which of the following is true regarding sigma subunits?

They bind to prokaryotic RNA polymerase to initiate transcription

Producing multiple proteins from one gene is a direct result of:

alternative splicing

Which of the following RNA sequences could form a hairpin loop?

AAAAAAAAUUUUUUUU

RNA polymerase will attach to the TATA box after it has been signaled to by the sigma subunit

false

Which would most likely effect the formation of a lariat?

Mutations in the branch point